R/objfnA_CRD.R

In designGLMM: Finding Optimal Block Designs for a Generalised Linear Mixed Model

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# Define an objective function
#' @export
objfnA_CRD <- function(des,ntmt,sige,means,probs=c(1)){
  # Calculate oP matrix
  oP<-diag(1/(1/means[des]+sige^2))
  # Calculate design matrix X
  Xmaster<-cbind(rep(1,ntmt),diag(1,ntmt))
  X<-t(sapply(des,function(x) Xmaster[x,]))
  # Set up contrasts
  cm<-matrix(0,nrow=ntmt,ncol=ntmt)
  cm[upper.tri(cm, diag = FALSE)]<--1
  cm<-cm+diag((ntmt-1):0)
  cm<-cbind(rep(0,ntmt),cm)
  cm<-matrix(cm[1:(ntmt-1),],nrow=(ntmt-1))
  cm<-rbind(c(1,rep(0,ntmt)),cm)
  cm<-cm/rowSums(cm^2)
  inversematrix<-try(solve(cm %*% t(X) %*% oP %*% X %*% t(cm)),silent=TRUE)
  if(class(inversematrix)=="try-error") ret<-1e160 else ret<-sum(diag(inversematrix))-inversematrix[1,1]
  ret
}